A Novel Primary-Side Regulation Technique for Active-Clamp Forward Converter

This paper proposes a novel primary-side regulation method of an active-clamp forward converter (ACFW) without using tertiary winding. The proposed method offers the tight regulation of output voltage under load fluctuations. The output voltage is estimated by sensing input voltage, input current, and clamp capacitor voltage. A control loop in the primary side is designed by analyzing the effect of the parasitic components to compensate the error of the estimated output voltage. The proposed method does not require any signal isolation or additional winding of transformer to simplify its implementation. The effectiveness of proposed method is verified by experiment by 100-kHz 200-W prototype ACFW.